LIBS and pXRF validation for the removal of Pb by bio-CaCO 3 nanoparticles from contaminated water

In this work, laser-induced breakdown spectroscopy (LIBS) was applied to qualitatively evaluate lead adsorbed from industrial wastewater by nano-CaCO 3 . Eggshell as a natural source of CaCO 3 has been used as a sorbent owing to its low cost and unrivalled adsorption capacity to remove Pb from contaminated water. The structure and morphology of CaCO 3 nano-powders were investigated using scanning electron microscopy (SEM), transmission electron microscope (TEM) and Fourier transforms infrared (FTIR). LIBS results were experimentally validated by the results obtained using portable X-ray fluorescence spectroscopy (pXRF) and energy dispersive X-ray (EDS), which confirmed the feasibility of using LIBS to detect traces of Pb ions, while the adsorption process is applied under governing parameters. Langmuir and Freundlich isotherm models were used to model the experimental data. The kinetics of adsorption mechanisms were studied using Lagergren's pseudo-first-order and McKay and Ho's pseudo-second-order. The obtained results demonstrated that bio-CaCO 3 nanoparticles could be used as an effective lead-sorbent from wastewater. Accordingly, it is possible to utilize this adsorption technique as a promising practical approach for the treatment of lead-contaminated industrial wastewater and its recirculation. Graphical abstract Highlights Natural nano CaCO 3 from eggshell was prepared mechanically as a low-cost adsorbent and characterized by SEM, TEM, and FTIR. The capacity of removing Pb (II) by nano-CaCO 3 was dependent on pH, metal concentration and contact time . LIBS was used for qualitative analysis of adsorbed Pb (II) and the results were validated with those obtained by EDX and pXRF spectrometry; in addition, isotherm models and kinetics of adsorption mechanisms were investigated.